Mission scientists have found Pluto to be 1,473 miles (2,370 kilometers) in diameter, somewhat larger than many prior estimates. Images acquired with the Long Range Reconnaissance Imager (LORRI) were ...

For the most part, our moon is nothing particularly special. It isn’t home to a series of active volcanoes, a thick atmosphere chalked full of nitrogen (with oceans of liquid hydrocarbons), or ...

This composite image shows color views of Pluto (right) and its largest moon Charon as they appeared on July 11, 2015 to NASA's New Horizons spacecraft ahead of a historic flyby on July 14.

Pluto's unusual eccentricity and tilt is likely due to its interactions with neighboring Neptune and other giant planets, ...

The second part of this question is much easier to answer than the first. We will definitely get a different number for Eris’ size once a spacecraft visits it. Spacecraft measurements can be thousands ...

In 2006, several months after New Horizons launched into space, Pluto stopped being a planet. That was according to the world's top astronomers, who said the celestial body failed to meet one of the ...

WASHINGTON (Reuters) - Dwarf planet Eris, similar in size to its better-known cosmic cousin Pluto, has remained an enigma since being discovered in 2005 lurking in the solar system's far reaches.

Forbes contributors publish independent expert analyses and insights. An award-winning reporter writing about stargazing and the night sky. It's time to move on from the problematic “Is Pluto a planet ...

The Hubble Space Telescope may be getting old, but it still has excellent spotting power — witness its discovery of a fourth moon of Pluto, which is between 8 miles and 21 miles in diameter. Says ...

Finally, a family portrait of Pluto is beginning to emerge! For the first time ever, astronomers have captured two never-before-photographed moons orbiting Pluto. NASA's New Horizons spacecraft ...